The present disclosure relates to a developing device of a non-contact developing system, an image forming apparatus including a developing device, and a magnetic pole position correcting method applied to a developing device.
In an image forming apparatus such as a copier or a printer that forms an image on a paper sheet by an electrophotographic system, a developing device is installed. The developing device develops, with toner, an electrostatic latent image that has been formed on a photoconductor drum (image carrier). The developing device includes a developing roller that is disposed separate from the photoconductor drum by a predetermined gap. One of known developing systems is a non-contact developing system in which developer is magnetically drawn up from a developer storage chamber to the surface of the developing roller, and toner is flown from the developing roller to the electrostatic latent image on the photoconductor drum by an electric field generated by a developing bias applied to the developing roller.
There is known a developing device of the above-mentioned non-contact developing system in which the developing roller is controlled to operate at a linear speed higher than that of the photoconductor drum. In this developing device, the linear speed of the developing roller is adjusted in correspondence with the operation mode of the image forming apparatus.
In addition, a cooling fan for cooling a cooling target is provided in a conventional image forming apparatus, wherein the cooling target is an exposure device, a developing device, a fixing device and the like provided in the image forming apparatus. The cooling fan is configured to blow air to the devices in the image forming apparatus. In addition, this type of image forming apparatus includes a temperature sensor in the periphery of the cooling target, and the blowing amount of the cooling fan is adjusted based on the temperature detected by the temperature sensor.